一种可倾斜六旋翼无人机容错控制方法

常规六旋翼无人机在单个旋翼完全失效后, 存在姿态与高度不完全可控的情况, 此时采取降级控制策略会 使无人机失去静态悬停能力. 针对此问题, 本文提出了一种可倾斜旋翼的容错控制方法, 在经典旋翼结构布局的基 础之上, 将其中一个旋翼设计成可倾斜结构, 通过倾斜角度的改变与控制分配重构, 无人机在任意单个旋翼完全失 效后均能保持力与力矩的平衡. 利用线性规划方法得到无人机的可达力矩集, 同时对电机饱和度进行分析, 确定了 不同旋翼失效后的最优倾斜角. 搭建飞行测试平台进行对比验证, 实验结果表明, 本文提出的方法具有良好的容错 效果与鲁棒性, 能够保证六旋翼无人机在故障后的稳定飞行与平稳降落.     

Routing for predictable Multi-Layered Satellite Networks

Multi-Layered Satellite Network (MLSN), especially LEO/MEO satellite network, consisting of low and medium earth orbit satellites, is capable of providing higher coverage and better service than single-layered one. Its performance in deployment, however, is mainly encumbered by obsolete routing protocols and algorithms. This paper takes the predictability of satellite movements into consideration, based on which a novel routing protocol Predictable Satellite Network Routing Protocol (PSNRP)—is proposed. In this protocol, every topology change due to satellite movement is either described as a predictable or an unpredictable change. On the basis of PSNRP, we import a heuristic routing algorithm for satisfying Quality-of-Service (QoS) requirements from network users, which is convinced as a Non-deterministic Polynomial Complete problem. The QoS requirements in this paper mainly refer to end-to-end delay, bandwidth and package loss rate. In addition to obtaining better routing performance, PSNRP successfully allocates calculation tasks evenly among all nodes, separates user data from protocol control data and achieves stronger robustness against satellite failures and link congestions. The superiority of our routing scheme is proved by simulation results.     

Effects of path angle changes on the times for ballistic and visually-controlled two-component arm movements

Although several Predetermined Motion time Systems mention the effects of change of path angle during a movement, there does not appear to be any experimental evidence for the quoted effects. Here we report effects of angle changes between zero and 180° during the movement, with and without an intervening target at the end of the first component of the movement. The effects are variable: with ballistic movements without an intervening target there is an increase of MT with path angle change; when there is an intervening target the MT of the first component decreases with change of path angle, while that of the second component increases, so that the total movement time is independent of the change in path angle. When the movements are made under visual control, with no intervening target, MT increases with change of path angle, whereas when there is an intervening target, there is no effect of change of path angle, either on the first or second component of the movement. Thus the occurrence of movement time increments is dependent on the form of motor control and the way in which the path angle change occurs.     

Fault diagnosis and monitoring of oscillatory failure case in aircraft inertial system

A method for oscillatory fault detection and isolation is presented and used to detect oscillatory failures of redundant aircraft sensors involved in the computation of flight control laws. The objective is to switch off the erroneous sensor and to compute a consolidated parameter using data from valid sensors, in order to eliminate any anomaly before propagation in the control loop. The benefit of the presented method is to improve the consolidation process with a fault detection and isolation approach when only few sources (less than three) are valid. Different techniques are compared to accurately detect any behavioral change of the sensor outputs. The approach is validated on a normalized real flight data set.     

Directional control-response relationships for mining equipment

A variety of directional control-response relationships are currently found in mining equipment. Two experiments were conducted in a virtual environment to determine optimal direction control-response relationships in a wide variety of circumstances. Direction errors were measured as a function of control orientation (horizontal or vertical), location (left, front, right) and directional control-response relationships. The results confirm that the principles of consistent direction and visual field compatibility are applicable to the majority of situations. An exception is that fewer direction errors were observed when an upward movement of a horizontal lever or movement of a vertical lever away from the participants caused extension (lengthening) of the controlled device, regardless of whether the direction of movement of the control is consistent with the direction in which the extension occurs. Further, both the control of slew by horizontally oriented controls and the control of device movements in a frontal plane by the perpendicular movements of vertical levers were associated with relatively high rates of directional errors, regardless of the directional control-response relationship, and these situations should be avoided.

Statement of Relevance:The results are particularly applicable to the design of mining equipment such as drilling and bolting machines, and have been incorporated into MDG35.1 Guideline for bolting & drilling plant in mines (Industry & Investment NSW, 2010). The results are also relevant to the design of any equipment where vertical or horizontal levers are used to control the movement of equipment appendages, e.g. cranes mounted to mobile equipment and the like.     

A method of evaluating VDT screen layout by eye movement analysis

Abstract

The method for evaluating VDT screen layout by eye movements is studied. When the subjects read from the VDT screen, the change in their line of sight was measured by their eye movements. The measured eye movement patterns were divided into the sequential and rereading processes. When related to these characteristics, the performance of subjects was found to be good when the sequential process predominated over the rereading process. The eye movement pattern was shown to change with screen layout. The eye movement pattern proved effective in determining that tabular format is more legible than textual format. This confirmed the usefulness of the method of evaluating VDT screen layout by the eye movement pattern.     

An experimental study on the role of graphical information about hand movement when interacting with objects in virtual reality environments

In this series of experiments, we investigated whether a crude representation of the hand that was extinguished at movement onset improved performance when compared to a no-feedback situation. Subjects performed simple reach to grasp movements in a virtual environment in two experiments. In Experiment 1, trials were blocked so that subjects were aware that a graphical representation of the hand would either be available throughout the movement (FA), be removed at movement onset (FAB), or not be available (NF). In Experiment 2, trials were randomized so that subjects were unaware of whether feedback would be available throughout the trial or removed at movement onset. Our results indicated that when subjects were aware of the availability of graphical feedback, the FAB condition improved performance compared to the NF condition. Furthermore, movement time was similar in the two feedback available conditions (FA, FAB). In contrast, for the randomized trial presentation, the positive influence of the FAB condition was diminished. These results suggest that visual feedback available prior to movement onset can be used to calibrate the proprioceptive system and improve performance over a no feedback situation. These results can be applied by designers of virtual environments to solve problems related to occlusion of important environmental information by the hand as users reach to grasp and manipulate objects.     

Impact of aviation highway-in-the-sky displays on pilot situation awareness

Thirty-six pilots (31 men, 5 women) were tested in a flight simulator on their ability to intercept a pathway depicted on a highway-in-the-sky (HITS) display. While intercepting and flying the pathway, pilots were required to watch for traffic outside the cockpit. Additionally, pilots were tested on their awareness of speed, altitude, and heading during the flight. Results indicated that the presence of a flight guidance cue significantly improved flight path awareness while intercepting the pathway, but significant practice effects suggest that a guidance cue might be unnecessary if pilots are given proper training. The amount of time spent looking outside the cockpit while using the HITS display was significantly less than when using conventional aircraft instruments. Additionally, awareness of flight information present on the HITS display was poor. Actual or potential applications of this research include guidance for the development of perspective flight display standards and as a basis for flight training requirements.     

A method of evaluating VDT screen layout by eye movement analysis.

The method for evaluating VDT screen layout by eye movements is studied. When the subjects read from the VDT screen, the change in their line of sight was measured by their eye movements. The measured eye movement patterns were divided into the sequential and rereading processes. When related to these characteristics, the performance of subjects was found to be good when the sequential process predominated over the rereading process. The eye movement pattern was shown to change with screen layout. The eye movement pattern proved effective in determining that tabular format is more legible than textual format. This confirmed the usefulness of the method of evaluating VDT screen layout by the eye movement pattern.     

Head-operated computer controls: effect of control method on performance for subjects with and without disability

Head-operated computer controls provide an alternative means of computer access for people with physical disabilities. A person's ability to use such head controls may be reduced if he or she experiences neck movement limitations. Five experimental methods of compensating for neck movement limitations were evaluated in comparison to a standard head control interface. Twenty-two subjects without disabilities and three subjects with multiple sclerosis performed icon acquisition exercises using the standard interface and each of the five experimental compensation methods. Subjects without disabilities had less tendency to overshoot the target icons when using an interface with decreased sensitivity or one in which head movements controlled cursor velocity rather than cursor position (p<0.05). Subjects with multiple sclerosis tended to be more accurate when using an interface with increased sensitivity, and had less tendency to overshoot icons when using head movements to control cursor velocity rather than cursor position. Overall, subjects tended to demonstrate faster performance when using an interface with reduced sensitivity.     

Effects of anomalous characters and small stroke omissions on eye movements during the reading of Chinese sentences

We investigated the influence of typographical errors (typos) on eye movements and word recognition in Chinese reading. Participants' eye movements were tracked as they read sentences in which the target words were presented (1) normally, (2) with the initial stroke of the first characters removed (the omitted stroke condition) or (3) the first characters replaced by anomalous characters (the anomalous character condition). The results indicated that anomalous characters caused longer fixation durations and shorter outgoing forward saccade lengths than the correct words. This finding is consistent with the prediction of the theory of the processing-based strategy. Additionally, anomalous characters strongly disrupted lexical processing and whole sentence comprehension, but small stroke omissions did not. Implications of the effect of processing difficulty on forward saccade targeting for models of eye movement control during Chinese reading are discussed.     

Changing the role of the air traffic controller: how will free flight affect memory for spatial events?

At present, air traffic controllers (ATCOs) exercise strict control over routing authority for aircraft movement in airspace. The onset of a free flight environment, however, may well result in a dramatic change to airspace jurisdictions, with aircraft movements for the large part being governed by aircrew, not ATCOs. The present study examined the impact of such changes on spatial memory for recent and non-recent locations of aircraft represented on a visual display. The experiment contrasted present conditions, in which permission for manoeuvres is granted by ATCOs, with potential free flight conditions, in which aircrew undertake deviations without explicit approval from ATCOs. Results indicated that the ATCO role adopted by participants impacted differently on short-term and long-term spatial representations of aircraft manoeuvres. Although informing participants of impending deviations has beneficial effects on spatial representations in the short term, long-term representations of spatial events are affected deleteriously by the presentation of subsequent information pertaining to other aircraft. This study suggests strongly that recognition of the perceptual and cognitive consequences of changing to a free flight environment is crucial if air safety is not to be jeopardized.     

Interaction effects in simultaneous motor control and movement perception tasks

Recent findings in neuroscience suggest an overlap between those brain regions involved in the control and execution of movement and those activated during the perception of another’s movement. This so called ‘mirror neuron’ system is thought to underlie our ability to automatically infer the goals and intentions of others by observing their actions. Kilner et al. (Curr Biol 13(6):522–525, 2003) provide evidence for a human ‘mirror neuron’ system by showing that the execution of simple arm movements is affected by the simultaneous perception of another’s movement. Specifically, observation of ‘incongruent’ movements made by another human, but not by a robotic arm, leads to greater variability in the movement trajectory than observation of movements in the same direction. In this study we ask which aspects of the observed motion are crucial to this interference effect by comparing the efficacy of real human movement to that of sparse ‘point-light displays’. Eight participants performed whole arm movements in both horizontal and vertical directions while observing either the experimenter or a virtual ‘point-light’ figure making arm movements in the same or in a different direction. Our results, however, failed to show an effect of ‘congruency’ of the observed movement on movement variability, regardless of whether a human actor or point-light figure was observed. The findings are discussed, and future directions for studies of perception-action coupling are considered.     

An experimental study of pilots' control characteristics for flight of an STOL aircraft in backside of drag curve at approach and landing.

In general, most vehicles can be modelled by a multi-variable system which has interactive variables. It can be clearly shown that there is an interactive response in an aircraft's velocity and altitude obtained by stick control and/or throttle control. In particular, if the flight conditions fall to backside of drag curve in the flight of an STOL aircraft at approach and landing then the ratio of drag variation to velocity change has a negative value (delta D/delta u less than 0) and the system of motion presents a non-minimum phase. Therefore, the interaction between velocity and altitude response becomes so complicated that it affects to pilot's control actions and it may be difficult to control the STOL aircraft at approach and landing. In this paper, experimental results of a pilot's ability to control the STOL aircraft are presented for a multi-variable manual control system using a fixed ground base simulator and the pilot's control ability is discussed for the flight of an STOL aircraft at backside of drag curve at approach and landing.     

基于全身力矩控制的双腿轮机器人跳跃方法研究

双腿轮机器人由于内在不稳定性以及强耦合非线性特性, 其运动控制尤其是高动态运动控制非常困难. 为此, 提出基于最优力分配的全身力矩控制框架, 可同时实现双腿轮机器人的自平衡与躯干位姿控制; 为提高双腿轮机器人在高速运动时跨越垂直障碍物的能力, 提出应对垂直障碍的跳跃动作规划方法, 并基于全身力矩控制框架进行控制与实现; 通过分析简化的轮式倒立摆模型, 得到腾空时飞轮转动对俯仰姿态的动力学影响, 实现腾空阶段俯仰姿态的调整. 设置连续跳跃仿真实验与有无飞轮调整的俯仰姿态对比实验, 其仿真结果证明所提方法的有效性与鲁棒性.     

The asymptotic and finite sample distributions of OLS and simple IV in simultaneous equations

In practice structural equations are often estimated by least-squares, thus neglecting any simultaneity. It is examined when this may be justifiable. Assuming data stationarity and existence of the first four moments of the disturbances the limiting distribution of the ordinary least-squares (OLS) estimator in a linear simultaneous equations model is derived. In simple static and dynamic models the asymptotic mean squared error of this inconsistent estimator is compared with that of consistent simple instrumental variable (IV) estimators and cases are depicted where—due to relative weakness of the instruments or mildness of the simultaneity—the inconsistent estimator is more precise. In addition, it is examined by simulation to what extent these first-order asymptotic findings are reflected in finite sample, taking into account non-existence of moments of the IV estimator. Dynamic visualization techniques enable to appreciate any differences in precision over a parameter space of a much higher dimension than just two, through colored animated image sequences (which are not very effective in print, but much more so in live-on-screen projection).     

Altitude control in simulated flight using 3‐D objects and terrain texture

Abstract— In this study, the effects of manipulating the properties of 3‐D objects and terrain texture on the control of altitude in simulated flight has been investigated. 3‐D objects were found to be as effective as terrain texture for controlling altitude, and this result was interpreted as suggesting that both terrain texture and 3‐D objects can serve as effective carriers of information about motion parallax and optical expansion and contraction. The present results, which were obtained using a vertically defined flight task, are inconsistent with the findings of Patterson et al., who reported that 3‐D objects were more effective than terrain texture for controlling a horizontally defined heading task. The present results indicate that, when terrain texture is present, the motion parallax or optical expansion associated with the presence of 3‐D objects does not improve altitude control.     

Fault management in process control: eye movements and action

Operators controlled a simulated thermal hydraulic system based on Crossman's waterbath task. They were required to keep the system at set points for temperature, level and flow rates. The system was subjected to disturbances and to failures, which the operators were required to manage. Behavioural data were collected in the form of keystroke commands, and in addition eye movements were measured. Evidence for 'cognitive lockup' and for a preference for serial fault management were found. Fixation durations do not change, but faulty subsystems are examined more frequently. During lockup other subsystems may be examined but action on them is delayed. Eye movements give considerable additional insight into the nature of process control information processing compared with traditional measures of operator performance.     

一种多飞行器自主编队飞行智能仿真系统研究

为缩小多机自主编队飞行理论研究与实际应用的差距,加快导航与控制系统从设计到产品实现的过程,提出了一种用于多飞行器自主编队飞行的智能仿真系统.该仿真系统采用多通道信息采集设备、多通道星座模拟器、协同飞行仿真控制设备,将真实飞行设备接入闭环仿真,有效验证了导航与控制系统方案的可行性.该仿真系统中,用同一时钟模块控制多通道星...     

Oscillatory failure case detection in the A380 electrical flight control system by analytical redundancy

This paper focuses on failure detection in the electrical flight control system of Airbus aircraft. Fault tolerance is designed into the system by the use of stringent processes and rules, which are summarized below. Monitoring of the system components is part of this fault-tolerant design. This paper covers the particular case of oscillatory failure monitoring in the electrical flight control system. The main characteristics and consequences of these failures are presented. The detection of oscillatory failures on the A380 is considered, together with the concept of analytical redundancy to detect these failures. A nonlinear actuator model is used to generate a residual on which the failure is detected by oscillation counting. Real application and benefits of the overall method are also presented. The results are highly satisfactory and the overall method is currently implemented on A380 flight control computers.